Inflatable core for use in casting hollow concrete units



@do 259 E949. C. B. MATHEWS ET AL 2,485,898

INFLATABLE CORE FOR USE IN CASTING HOLLOW CONCRETE UNITS Filed July 25, 1945 2 Sheets-Sheet l invento/'.41

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INFLATABLE CORE FOR USE IN CASTING HOLLOW CONCRETE UNITS Filed July 25,. 1945 v2 sheets-sheet 2 Atto eyd/ Patented Oct. 25,1949

INFLATABLE CORE FOR USE IN CASTING IHOLL'OW CONCRETE UNITS Charles B. Mathews, Ilkley, and John G. Ambrose,

Fossebridge, England Application July 25, 1945, Serial No. 606,97

In Great Britain June 20,' 1944 (Cl. .Z-128) 8Claims. 1

.Thisdnventionirelates to inatable cores for use in .castinghollow concrete units and in particular with non-.circular cores.

.Such cores consist, in general,.of a number of inflatable tubes arranged longitudinally `side by side. lIn some cases. the .tubes are separate tubes and 'in othersthey areformed by bending a single tube upondtself.

In any case the non-circulariniiatable unit as a wholehasto be enclosed in a cover.

It is necessary, `for the successful operation of such -cores,fthatl when, after the casting operation has beencompleted and the concrete has to some extent set, the core on deflation will separaterom walls ofthe hollow slab so as to permit Withdrawal of vthe* core.

Thepresent invention isconcerned primarily with an enclosing outer cover for such cores and has .for its object-soto construct this outer cover thatv on deflation the core can ybe easily .and quickly withdrawn from the cast unit.

In accordance with the invention We construct the .cover of two -steelvor .like plates `flexibly connected together throughout their length.

The invention consists broadly of a cover for containingu the inflatable elements of inflatable cores for use in the casting of hollow concrete units comprising topuancl. bottom `metal plates exibly connected together longitudinally, and further comprises an inflatable core for use in the casting of hollow concrete units comprising iniiatable tubesl located; bletweeiriand; associated with topand bottom plates flexibly connected together. 'so that the distance separating such plates Itransversely can be varied by the ination and.' deflation ofthe inatable tube.

The 'invention' is'illu'strated in the accompanying drawing,

Figure 1 being a transverse sectional perspective view of one form of the invention.

Figure 2 is a similar View of another method of carrying out the invention.

Figure 3 is a transverse sectional view of the construction shown in Figure 2.

Figure 4 is a similar view of a modification of the arrangement shown in Figures 2 and 3.

Figure 5 is a section on the line A-A of Figure 4 and Figures 6 and 7 are longitudinal sectional and end views respectively of a further method of carrying out the invention.

Referring to these drawings and particularly to Figure 1, the numeral I indicates top and bottom plates which may conveniently be of steel. To the ends of these plates Il flexible side walls 2 are connected. Such side walls may advantageously be of irubberised cotton and maysbe provided with rods or beads 3 attheir longitudinal edges to enable them to be clamped `se curely in position by means of the clamping strips 4.

The cover is shown in itsdistended position within a concrete unit, the'numeral 5. indicating inflating tubes of which :theremay be any required number. In the drawing, three-:argindicated, but it will -be understood that thecentral onemight quite'well be replaced .byv a solid separator.

Referring now to Figures 2 and 3, the plates I, in this example, have bridge pieces orfba'ttens 6 attached to their innerfaces, thefinfl'ating :tubes 5 are encased in outer covers 5a, that are'provided with longitudinally spa-ced sleeves I that form eyeletsV and the plates I are connected together and to the inflating tubes by means of the longitudinal lacing' rods 8 which ypass through `the bridge pieces 6 and the eyelet sleeves .'I, which are cut away at the positions 9 'td-accommodate the ends of the bridge lpieces'zi. Figure 2 shows the iniiation tubes 5 encased in their usual outer covers. 5a operating to effect the separationfof the top and bottom plates Ivand it will be understood that the inflation pressure, in all casca-need only be suiicient to support-the weight offconcrete resting on thetopfof .the `core-duringthe casting operation.

Figures 4 and 5, so .far asthefinventionis. concerned, are precisely the same as the construction shown inFigures 2 and 3 but are included to show a case where four, instead of two, inflating tubes 5b are employed, ,the twin .inflation tubes proper on each side being .enclosedin la composite outer fabric casing as shown. Figure 5, however, also serves t0 show how a pulling handle I0 may be arranged to facilitate withdrawal of the core as a whole from the cast unit and also indicates at II the tubes for connection to the inlating pump or pumps.

Figures 6 and 7 show more or less diagrammatically a further method of carrying out the invention. In this case, Wooden battens I2 are attached to the inner surfaces of the plates I, screw type eyelet rings 'Ia are screwed into the side walls of the battens, and the plates I are connected together and to the iniiation tubes 5 by longitudinal lacing rods 8 threaded or laced through rings 'la and eyelet sleeves I, much in the manner previously described with reference to Figures 2 and 3.

Intermediate the two inating tubes 5, wooden spacers or stop blocks I2a may be provided or,

of course, the whole lateral space between the plates I may be filled with ination tubes. The inflation tubes may be connected together by a manifold device I3 so that they can both be inflated simultaneously by way of a common air inlet tube and valve device I4. Pulling handles I5 attached to the plates i may be provided.

It will vbe plain that, in all cases, on deflation of the inflatable tube or tubes, the top plate will fall away from the concrete and the flexible side walls will collapse sufciently to loosen the whole core structure from the surrounding' concrete and enable it to be withdrawn.

We claim:

1. An inatable core for use in the casting of hollow units of concrete or like material comprising rigid plates constituting the top and bottom walls of the core, and inflatable exible wall means hingedly connecting said plates at each side in a longitudinal direction and which constitutes the side walls of the core.

2. An inflatable core for use in the casting of hollow units of concrete and the like comprising rigid plates constituting the top and bottom parts ofthe core, inflatable elements located between the plates at each side thereof, outer fabric casings containing the inatable elements and constituting the side walls of the core, and means for hingedly connecting said outer fabric casings to said plates.

3. An inflatable core for use in the casting of hollow units according to claim 2 and including a manifold connecting the inflatable elements, whereby the inflatable elements are inflated and deflated simultaneously.

4. An inflatable core for use in the casting of hollow units of concrete and the like comprising relatively rigid plates constituting the top and bottom walls of the core, tubular inflatable means extending longitudinally between said plates along each side thereof and which constitute the side walls of the core, a rst set of longitudinally spaced eyelet means carried by said top and bottom plates, a second set of longitudinally spaced eyelet means carried by said inflatable means, and rods extending through and interlacing both sets of said eyelet means for connecting said inllatable means to said plates.

5. An inflatable core as defined in claim 4,

wherein said inflatable means is comprised of an outer tubular cover member to which said eyelet means are secured and an inner tubular member adapted to be connected to a source of fluid pressure.

6. An inflatable core for use in the casting of hollow units of concrete and the like comprising relatively rigid plates constituting the top and bottom walls of the core, tubular inflatable means extending longitudinally between said plates along each side thereof and which constitute the side walls of the core, a plurality of spaced sleeves secured to and extending longitudinally along said inflatable means, a plurality of spaced battens secured to the undersides of said plates, said battens being placed transversely of the longitudinal axis of said plates in the spaces between said sleeves and including eyelet means aligned with the latter, and rods extending through said sleeves and eyelet means for connecting said inflatable means to said plates.

7. An inflatable core for use in the casting of hollow units of concrete and the like comprising relatively rigid plates constituting the top and bottom walls of the core, tubular inflatable means extending longitudinally between said plates along the sides thereof and which constitute the side walls of the core, a plurality of spaced sleeves secured to and extending longitudinally along said inflatable means, a plurality of spaced battens secured to the undersides of said plates, said battens being placed transversely of the longitudinal axis of said plates and including eyelet rings located in the spaces between said sleeves, and rods extending through said sleeves and rings for connecting said inflatable means to said plates.

8. An inflatable core for use in the casting of hollow units of concrete and the like comprising relatively rigid plates constituting the top and bottom walls of the core, tubular inflatable means extending longitudinally between said plates along the sides thereof and which constitute the side walls of the core, a plurality of spaced sleeves l secured to and extending longitudinally along' REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,964,386 Nose June 26, 1934 2,170,188 Cobi Aug. 22, 1939 2,375,148

Terry May 1, 1945 

